#include<fstream>
#define NMAX 100010

using namespace std;

int n, m, vz[NMAX];

struct nod
{
	int x;
	nod* urm;
} *a[NMAX], *ultim[NMAX];

ifstream f("dfs.in");
ofstream g("dfs.out");

void Adauga(int x, int y)
{
	nod *q;
	if (a[x]==NULL)
	{
		a[x]=new nod;
		a[x]->x=y;  a[x]->urm=NULL;
		ultim[x]=a[x];
	}
	else
	{
		q=new nod;
		q->x=y; q->urm=NULL;
		a[x]->urm=q;
		ultim[x]=q;
	}
}

void Citeste()
{
	int i, x, y;
	f>>n>>m;
	for (i=1; i<=m; ++i)
	{
		f>>x>>y;
		Adauga(x, y);
		Adauga(y, x);
	}
}

void DFS(int x)
{
	nod *q;
	vz[x]=1;
	for (q=a[x]; q!=NULL; q=q->urm)
		if (!vz[q->x]) DFS(q->x);
}

int numar_cc()
{
	int nr=0, nod;
	
	for (nod=1; nod<=n; ++nod)
		if (!vz[nod])
		{
			++nr;
			DFS(nod);
		}
	return nr;
}

int main()
{
	Citeste();
	g<<numar_cc()<<"\n";
	f.close();
	g.close();
	return 0;
}